'Chemo Brain' May Start Before Breast Cancer Tx

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This study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

Women with breast cancer appear to experience deficits in working memory even before they undergo adjuvant chemotherapy.

Note that in all study groups, greater fatigue was associated with poorer test performance and more self-reported cognitive problems over time.

SAN ANTONIO -- "Chemo brain" is a real phenomenon among breast cancer patients, but it appears to start long before women undergo adjuvant chemotherapy, a researcher said here.

A study using functional MRI (fMRI) suggested that a month before chemotherapy was slated to start, women already experienced deficits in working memory, according to Bernadine Cimprich, PhD, RN, of the University of Michigan School of Nursing in Ann Arbor, Mich.

Women diagnosed with breast cancer, but who were slated just for radiation therapy, did better on memory tests performed during fMRI scanning while women without cancer did even better, Cimprich told reporters at the San Antonio Breast Cancer Symposium.

And across all the groups in the study, greater fatigue was associated with poorer test performance and more self-reported cognitive problems over time, Cimprich said.

The findings suggest that "chemo brain" is not the best way of thinking about what Cimprich called "cancer-related cognitive dysfunction."

Instead, the effect is probably due at least partly to the stress and fatigue associated with a cancer diagnosis and could be alleviated by interventions aimed at reducing fatigue, she suggested.

For this prospective study, the researchers enrolled 65 women with stages 0 through IIIa breast cancer, as well as 32 healthy, age-matched controls. Among the patients, 28 women were scheduled for adjuvant chemotherapy and 37 were to have radiotherapy alone for localized breast cancer.

Participants in the chemotherapy group performed a verbal working memory task with varying levels of difficulty during functional MRI scanning after surgery, a month before chemotherapy, and second time a month after chemotherapy.

The radiation patients had their testing after surgery, about a month before starting radiation, and again 5 months later, corresponding roughly to the length of the chemotherapy in the other group.

The healthy controls had their fMRI scans done after a negative mammogram and again 5 months later.

All the participants provided self-reports of cognitive function and fatigue at the same time points.

The researchers were interested in the left inferior front gyrus, a region that has been shown to be "extremely important" in working memory tasks, Cimprich said.

The chemotherapy group, she said, reported significantly greater severity of fatigue (P<0.05) and performed less well on the verbal memory task at the first test.

Indeed, "the patient groups, as a whole, showed less activation [in the target region] than controls," she said, but the radiotherapy group was intermediate between controls and chemotherapy patients.

Greater fatigue was correlated with poorer performance on the memory task, regardless of group, she noted.

On the other hand, there were few differences in the brain scans taken at the second time point, largely because the chemotherapy patients had recovered much of their ability, Cimprich said.

Kent Osborne, MD, of Baylor College of Medicine in Houston, called the findings "very interesting," adding that, in his own practice, he has "often wondered if [chemo brain is] "as much related to the worry, anxiety, and stress at to the treatment itself." Osborne moderated the SABCS press conference.

The study was supported by NIH and the National Institute of Nursing Research. Cimprich reported no conflicts of interest.

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